Psychopathology - OCD Flashcards
Give a family study into the genetic explanation for OCD
Nestadt et al. (2000) found that first-degree relatives (parents, siblings and
children) of OCD sufferers had a higher chance of developing the disorder.
12% chance for those with first degree relatives diagnosed with OCD
3% risk for control group ppts
Explain the genetic explanation of the COMT gene for OCD.
• There is a mutation of this gene which causes low levels of the enzyme catchecol-
o-methyltransferase (COMT).
• Enzymes break down (metabolise) other molecules, such as neurotransmitters
(anything ending in the suffix ‘-ase’ is an enzyme).
• This enzyme therefore regulates the amount of the neurotransmitter dopamine
in the brain.
• Low levels of the COMT enzyme means less dopamine is broken down, so high
levels of dopamine.
What is the SERT gene as a genetic explanation for OCD
• The SERT gene creates a protein, called a SERotonin
Transporter, which removes serotonin. Transporters
detect the amount of neurotransmitter in the synapse,
and remove from the synapse after it is released.
• When a mutation of this gene creates too much of the
serotonin transporter, serotonin levels go down
(because the transporter is removing serotonin from
the synapse)
What did Taylor find about OCD?
It’s more likely to polygenic he found there can be up to 230 candidate genes.
What is the Diathesis stress model?
According to the diathesis stress model certain genes leave some people more likely to suffer a mental disorder but it is not certain as some environmental stress is necessary to trigger the condition.
Diathesis = genetic vulnerability
Stress = environment
What is the neural explanation of seretonin?
Serotonin is important for the regulation of mood. It has an overall calming effect on the brain.
• Low levels of serotonin means that the brain
does not communicate information about
mood effectively.
• This reduction in functioning seems to be linked to OCD.
• Low levels of serotonin have been associated
with the symptoms of OCD e.g. anxiety
• Piggot et al. (1990) reported
Explain the neural explanation of dopamine
Dopamine is a neurotransmitter which
is important for maintaining interest and
motivation.
High levels of dopamine could therefore
help to maintain a compulsive thought
or behaviour, therefore leading to some
of the symptom of OCD, in particular,
compulsive behaviours.
Explain the neural pathway
• The orbitofrontal cortex is a region which converts
sensory information into thoughts and actions.
• PET scans have found higher activity in the orbitofrontal
cortex in patients with OCD when, for example, a
• patient is asked to hold a dirty item with a potential
germ hazard.
• Heightened activity in the orbitofrontal cortex may
increase the conversion of sensory information to
actions (behaviours) which results in compulsions.
What is seretonin for?
Regulates mood by inhibiting excessive neural activity.
What is dopamine for?
Controls motivation by transmitting information in the brains pleasure and motor pathways.
How do SSRis work?
Type of antidepressant that works by blocking the reuptake of serotonin in the synaptic cleft increasing the concentration and improving mood and reducing symptoms of depression.
Prozac
How do SNRIs work?
Block the reuptake of both serotonin and norepinephrine increasing levels in the synapse to enhance mood.
Venlafaxine
What are benzodiazepines?
Drugs that enhance the effect of the inhibitory neurotransmitter GABA reducing neural activity and induces relaxation.
Diazepam
How do tryciclic acids work?
Blocking the reuptake of seretonin into the post synaptic neurone increasing concentrations in the synapse.
Imipramine
